package 链表;

/**
 * https://leetcode-cn.com/problems/linked-list-cycle/
 */
public class _141_环形链表 {
    public boolean hasCycle(ListNode head) {
        if (head == null || head.next == null) return false;
        ListNode slow =head;
        ListNode fast = head.next;
        while (fast!=null && fast.next != null){
            slow = slow.next;
            fast = fast.next.next;
            //判断地址是否相同
            if (slow== fast) return true;

        }
        return false;
    }
}
